cheatsheets/javascript-arrays.md

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---
title: JavaScript arrays
layout: default
---
## JavaScript arrays
array = [a,b,c,d,e]
array[1] //=> b
array.indexOf(b) //=> 1
### Subsets
array.slice(1) //=> [b,c,d,e]
array.slice(1,2) //=> [b]
// Destructive
re = array.splice(1) // re = [b,c,d,e] array == [a]
re = array.splice(1,2) // re = [b,c] array == [a,d,e]
### Adding items
array.push(Z) // array == [a,b,c,d,e,Z]
array.unshift(Z) // array == [Z,a,b,c,d,e]
array.concat([F,G]) //=> [a,b,c,d,e,F,G]
### Taking items
array.pop() //=> e array == [a,b,c,d]
array.shift() //=> a array == [b,c,d,e]